OpenBSD strives to be the most secure UNIX derivation. Design principles, such as code auditing, extensive use of encryption, and careful configuration choices, combine to ensure OpenBSD's secure by default philosophy holds true. This article gives you a close look at the operating system so secure that it was once banned for use in a DEF CON competition, where crackers go after each other's systems.

and an addition to what Bink has said, i think a simple steps like these:

export PKG_PATH=/path/or/url/to/new/packages
pkg_add -u -F upgrade

is not a painful way to upgrade packages.

and i think the openbsd team should not change their installer either. its small and fast. its very rational and logical, a simple understanding of the english language is all it takes to install openbsd. ports install can always be done after the base installation.

rest of the system become static? how? there's many innovation happening in openbsd (e.g. pf, CARP, OpenBGPD, OpenVRRP, good wireless device support, etc.)